Improvement in transmitters for elxctro-harmonic



Patent eid luly20,1875.

Elicia ray VEJVJ'OR mg. V

W m M A 4v 7 Z W E. GRAY. Transmitter for Electra-Harmonic Telegraph;

45;: Ifiiliillliz'fifiifla? WITNESSES No;l65,728.

UNITED STATES ELISHA GRAY, OF

IMPRDVEMENT m. TRANSMITTER? F0 CHICAGO, ILLINOIS.

R. ELECTRO-HA RM ON lC. TELEGRA PHS.

Specification forming part of Letters Patent-No. 165,728.,deted July 20, 1875; application-filed June 23, 1875.,

To all whom it mag concern:

Be it ,knownthat l, ELISIIA GRAY, of Chi= cage, in the county of Cook and State of 1llinois, have invented certain new and useful Improvements in Transmitters for Electrollarmonie 'lelegraphs, of which the follo is a specification:

My invention relates to telegraphic apparatus of that class in which a circuit-breaking spring is automatically vibrated with sufficient rapidity to produce a musical tone.

in such instruments as heretofore constructed, so far as my knowledgeextends, electromageets, by which the'spring is attracted, have always been placed on one side of the vibra t tug bar or electrotome by which the musical note was produced. A tendency has conse, nuently existed toward the disturbance of its rihra'tions.

The objectof my invention is to remedy this defect; to which end my in'iprovemcnts consist in arranging upon opposite sides of the vibrating spring of the eiectro tome, electro-inagnets or such relative. power as to impart impulses of equal force upon each side of the vibrating spring alternately at equal iutervals, thus securing its isochronous vibration. My invention further consists in com bining, with the magnets and vibrating spring or reed, shunting wires so arranged as autowin g matically to transfer the current from one magnet to the other without the use ofa switch.

In the accompanying drawings, which show sc'niueh of my improvedapparatus as is necessary to illustrate the subject-matter herein claimed, Figure 1 is a plan or top view; and Fig. 2, a vertical transverse section therethrough, on the line 000:, Fig. 1.

The apparatus ismounted upon an ordinary base-hoard, A. A steel-bar spring or vibrating reed, ll, tunedto give a musical tone of a given pitch when thrown inro'vibrati'on is se cured by one end-to a-post, 6, while its free end extends between two pairs-of magnets,

.13 D E E, arranged transversely to the reeds inthe plane of its vibration, their poles being arranged just far enough apart to aceommoa datc this-vibratory movement. F F G G are binding-screws, to which the main and local battery wires are respectively connected.- The magnets D l) are wound with a resistance of about sixteen ohms or units of resistance,

about four ohms.

It is awed-known fact that when two magnets of different. resistances, other things being equal, are placed in the same circuit and a battery-current sent through them, the magnet having the higher resistance develops the strongermagnetism, which magnetism is stronger inproportion as the resistance is higher than thatlof the other magnet. In other Words, it"the magnets E E, when alone in the circuit, have a power, say, of four, their etfect will be diminished .to a power of one when nagnets D l) are let in, and-the power of the latter will rise from zero toiive.

The reed B is provided with spring contactpoints b 1), arranged one on each side thereof, intermediate between the .magnets and its supporting-post. When the reed is at rest these points are in contact with adjustingscrews t i, of binding-posts I l. i Fig. 1 shows the battery connections. The main line M L extends from the binding-screw Gr, through thence through the reed and its contact-point b to the binding-screw I thence to the binding screw G. The local circuit passes from the battery through thehinding-post F by the wire L to the magnets D'l) thcnce'by the wire L through the reed-supporting post 0, and the wire U to the magnets E E thence by the wire L to the himling-post 1*"; In addition to this a shunt-wire, S, passes from the hinding-post'll. to, the post 1, through the con- *tac -point b to the reed and its supportingpost O,where itconnccts with the .local circuit L L The. operation of the apparatus is asfollows: hen the local circuit is established the current does not pass through the magpassage through the shunt-wire S and contact-point li, vibrating reed 15, post .G, and wire Lfto the magnets E E thence by the wire L? to the other pole of the localhattery. The passage of this current develops in the latter magnet the power, say, of four, which is exerted upon the vibrating reed B, and draws it towardthe poles'of'the magnets.

while inn-gnets'E E have only a resistance of the wire 1 to the reed'supporting post 0;

netsD-"D hy the wire-L, as it finds an easier;

when the reed is moved a short distance in obedience to this impulse its movement causes the contact-point D-to separate from the binding-screw i, when of course the currentwill no longer flow through the shuntwire 8, but passes from the post F through the wire L directly to the magnets D D, and from thence through the wires L L to the magnets E- E; thence through the wire Lto the post F, which connects with the other pole of the local battery. power oi the magnets D D from. zero toe power of'five, while the other magnets drop from four to one. The result is, that the reed vibrates back toward the magnets D D with thesame force that it did toward the other lllfl-filiili'S-fllili? is, npower of four each way. When the points I) i come in contact again the magnets D- l) are cut out of the circuit by the establishment of the current through the shunt-wire S, and their power drops to zero, and the operation above described is repeated. This alternate opening and closing of the circuit takes plnce'with a frequency equal to the rate per second sufiicient to produce the fundamental tone of the vibrating reed. The

nuiin-line current is interrupted at every vibntion of the reed by the separation of the contact'points I) 2"; consequently a series of impulses corresponding in number with the said vibrations willbe, transmitted to a suitable receiver and reproduced in a tone of cor- 1'Gli,'2l.$ fullyexpln-nieu 1n sundry applications for Letters Patent of the United States for apparatus for transinittin g in usicel impressions This raises the scribed my name. resnondintr pitch to that of the vibrating worms or sounds teiegrephicniiy, heretofore tiled by me.

The advantages of any improvement are, that the impulses imported to the viii-rating reed, being eiihe'on both sides, its center of vibration coincides with the axis ofl the reed when at rest. The isoehrenous vibration of the reed is thus preserved in its integrity, and, consequently,. that of the electric Waves or impulses generated by it, which tronsmitted throughthe main line, which impulses determine those of the receiver, and the ribrating reed is prevented from being thrown out of tune with the receiver by variations in the buttery-power, which variations are liable to occur in the ordinary method.

I claim- L The combination, substnntinii'y as herei nhefore set forth, of the vibrating eicctro tome and magnets arranged on opposite sides thereof, of such relative capacity as to impart impulses of equal force at equal intervals upon each side of the vibrating electro-tome alternately, whereby its isoehronons vibration is secured.

2. The combination, substantially as hereinbefore set forth, of the vibrating reed, its connterpoise-mngnets, it local circuit, and the shunt Wire, whereby the current is automaticnlly changed to each set of magnets.

"In testimony whereof, I have hereunto sub ELISHA GRAY. Witnesses:

WM. J. Pnizron,

E. G. DAVIDSON. 

